Fasciola hepatica has digeneric life cycle. The primary host in which the adult liver fluke lives is sheep. The metacercaria larva is the infective stage of F. hepatica for sheep because it develops into adult only inside the sheep. The sheep gets infection by grazing on leaves and grass blades to which the cysts are attached. The sporocyst larva ofliverfluke formed from the miracidium larva. Glands, brain, eye spots and apical papilla of ^Tiiracidium degenerate and disappear in sporocyst. Sporocyst moves about in the tissue of host absorbing nutrition from it and produce redia larva. Each redia produces 14−20 cercaria larva. The cercaria larva enters the digestive gland of snail. After an active life of few days the cercaria losses its tail and undergoes encystment on some equatic plants to become the metacercaria larva.